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E T Wright

Publications and source records attributed to E T Wright.

At least 19 recordsLinked to original sources
PubMed1995

Specific single-stranded breaks in mature bacteriophage T7 DNA.

Both rate zonal centrifugation and gel electrophoresis have revealed that the mature double-stranded DNA of bacteriophage T5 has single-stranded breaks (nicks) at specific sites. Neither of these procedures has previously revealed site-specific nicks in the double-stranded DNA of other bacteriophages, including T7. In the present study, denaturing gel electrophoresis, followed by specific DNA detection, reveals that a small fraction of mature T7 DNA molecules, like most T5 DNA molecules, has site-specific nicks. The procedure of specific detection is to probe with an oligonucleotide specific for one of the ends of T7 DNA. If position 0.0 is the left genetic end and position 100.0 is the right genetic end of T7 DNA, the nicks on the 5' left-oriented strand are at 11.3, 12.4, 65.7, 79.2, and 86.0; the nicks on the 5' right-oriented strand are at 23.3 and 26.5 (+/- 0.5). The positions of the three rightmost nicks are indistinguishable from those of double-stranded breaks that produce previously demonstrated shorter than mature length DNAs packaged in vivo. We propose that the T7 nicks are produced by premature activity of the T7 terminase during DNA packaging.

Bacteriophage T7↗
PubMed1994

Prostatic fluid inflammation in prostatitis.

We studied expressed prostatic secretions from 106 patients with prostatitis to determine the longitudinal course of prostatic fluid inflammation. Prostatic fluid specimens were collected from 14 patients with acute bacterial, 13 with chronic bacterial and 79 with abacterial prostatitis. White blood cells per high power microscopic field of the expressed prostatic secretion were counted under a cover slip. Inflammation in the expressed prostatic secretion was considered to be consistent with prostatitis if there were 10 or more white blood cells per high power field. The 14 patients with acute bacterial prostatitis had a mean of 10 visits with a mean followup of 59 months. Inflammation resolved within 1 month in 9 patients with acute bacterial prostatitis but it recurred in 5 other patients in association with urinary tract infection. The 13 patients with chronic bacterial prostatitis had a mean of 10 visits with a mean followup of 58 months. Episodic inflammation in the expressed prostatic secretion associated with urinary tract infection was seen in all patients during followup. The 79 patients with abacterial prostatitis had a mean of 7 visits with a mean followup of 40 months. Resolution of inflammation in the expressed prostatic secretion occurred in 9 patients (11%). Inflammation in the expressed prostatic secretion at followup was seen in 70 patients (89%), and 27 of the 79 patients (34%) had 10 or more white blood cells per high power field of expressed prostatic secretion in all subsequent specimens. In cases of abacterial prostatitis, neither the initial expressed prostatic secretion white blood count nor the presence of symptoms reliably predicted subsequent inflammation. The data suggest that prostatic inflammation resolves in most patients with acute bacterial prostatitis and is episodic in patients with chronic bacterial or abacterial prostatitis.

Acute Disease↗
PubMed1990

Recovery of nuclei from glycol-methacrylate-embedded tissue.

The analysis of antigens, enzyme histochemical markers, and DNA has become an important part of the classification of some leukemias, lymphomas, and other neoplastic diseases. Many of the relevant antigens and most of the relevant enzyme histochemical activities are destroyed and others are less than optimally preserved in tissues embedded in hot paraffin. Most enzymatic activities and antigens are well preserved in tissues embedded at 4 degrees C in glycol methacrylate (GMA). The measurement of DNA content in neoplastic cells with the most commonly employed techniques depended on the availability of fresh suspensions of cells until the development by Hedley of methods that permit the recovery of nuclei from paraffin blocks for this purpose. In order to facilitate the analysis of antigens, enzymatic markers, and DNA from the same sample of tissue, we have developed a means of recovery of nuclei from GMA-embedded tissues. Twenty-microns-thick sections of GMA-embedded tonsil were either pretreated with an organic solvent (absolute ethanol or 2-ethoxyethanol) followed by rehydration in phosphate buffered saline (PBS) or directly rehydrated in PBS. The suspensions were formed mechanically by gentle sonication. The type of fixative and length of PBS rehydration were varied. Tissue fixed in 100% acetone, embedded in GMA, and rehydrated directly in PBS for six days gave the highest average yield of nuclei, 3.7 x 10(7) nuclei per gram tissue. In order to assess DNA binding of fluorescent dyes, 2-microns-thick GMA sections were stained with chromomycin, Hoechst 33342 (Sigma Chemical, St Louis, MO), and propidium iodide. Hoechst 33342 bound specifically to the nuclei with low background staining.

Benzimidazoles↗
PubMed1978

Anomalous vitamin E effects in mitochondrial oxidative metabolism.

Three different vitamin E effects, suggestive of specific antioxidant effects, were discovered in the protective action of vitamin E against respiratory decline (a decrease in mitochondrial respiration attributed to a "leakage" of electron transport radicals). No correlation was found between respiraotry decline and random lipid peroxidation. The mechanisms behind two of the three atypical vitamin E effects were defined. Both involve an artifact in the TBA assay for lipid peroxidation. This artifact occurs when TBA assays are carried out in the presence of sucrose and acetaldehyde; the latter is produced from ethanol, the solvent used to add vitamin E to preparations. The artifact in the TBA assay for peroxidations appears also to be responsible for differing interpretations of the hepatotoxic effect of ethanol.

Acetaldehyde↗
PubMed1978

Antioxidant effects in the development of Ehrlich ascites carcinoma.

The effect of Ehrlich ascites tumor growth on selenium-turnover rates and selenium-75 distribution in liver, kidney, and immunological tissues (spleen, thymus, and lymph nodes) was investigated in Swiss Webster mice that had been prelabeled with selenium-75. Ehrlich ascites tumor caused a decrease in the selenium-75 content of liver, kidney, and thymus; it also decreased the rate of the total-body selenium-turnover. In liver, depletion of selenium-75 was almost as great as that produced by a selenium and vitamin E-deficient diet. When mice had been fed an antioxidant-deficient diet, considerable quantities of selenium-75 were accumulated by the tumor; the specific activity of the tumor increased 9-fold over that in antioxidant-supplemented mice. The same diet produced a premature, and in some cases drastic, contraction in tumor volume. The possible significance of tumor-induced antioxidant deficiencies to the etiology of certain paraneoplastic syndromes is discussed.

Animals↗
PubMed1976

Pruritic skin diseases, psychological stress, and the itch sensation. A reliable method for the induction of experimental pruritus.

A method of inducing controlled levels of terminable itching was developed. This method consists of administering constant monophasic pulsations of electric current by means of noninvasive electrodes. Once experimental pruritus had been reliably reproduced, two variables, hypothesized to be relevant to the perception of itching, were investigated, viz, the presence of a positive or a negative history of a pruritic dermatosis, and the presence of a high or low level of psychological stress. Both variables were found to be related to the perception of itching, but in different manners. A positive history of a pruritic dermatosis lowered the threshold for the perception of itch stimuli, while a high level of psychological stress enhanced the ability to discriminate among the more intense itch stimuli, with no effect on the itch threshold.

Adolescent↗
PubMed1975

Novel interference in thiobarbituric acid assay for lipid peroxidation.

The thiobarbituric acid test for lipid peroxidation, when applied to a mixture of acetaldehyde and sucrose, produces a 532 nm aborbing chromogen which is indistinguishable from that formed by malonaldehyde and thiobarbituric acid. Unless special procedures are adopted to correct for this effect, the combined action of acetaldehyde and sucrose interferes seriously with the assay of lipid peroxidation reactions, notably those implicated in alcohol-induced liver injuries. However, this unusual thiobarbituric acid effect also can be used as a sensitive method for the detection of acetaldehyde.

Acetaldehyde↗